Tape cutter

ABSTRACT

To obtain a tape cutter in which comfortable use is ensured when a guard mechanism is interlocked with up/down motion of a sticking portion in view of a fact that a cut-well sharp blade can be fixed if safety of a finger is ensured at the edge. 
     A tape sticking portion separate from a blade and slidable up/down and a planar edge guard moving up/down together with the tape sticking portion are provided in front of the blade, and a pair of arm-like edge guards are provided on the opposite sides thereof such that they are opened/closed while interlocking with up/down movement of the sticking portion. Since safety of a finger is ensured at the edge and the guard arm is opened/closed automatically, the tape cutter can be used by an operation substantially similar to that of a conventional common tape cutter. Furthermore, a magnet is used for sustaining the open state of the guard arm and the sticking portion and its holder can incline when they are pulled to the reel side. Consequently, smooth and positive operation of the mechanism can be attained.

TECHNICAL FIELD

The present invention relates to a tape cutter.

BACKGROUND ART

Many and various types of desktop tape cutters have been developed andcommercialized. Among them, a number of impressive examples are roughlyclassified into the following three types. First, some tape cutters areunique in a tape-mounting method or in a reel-supporting method,according to which a user can replace a tape from the side while leavinga reel supported by a main body, or according to which a tape is laid onits side with a rotational shaft extending in the vertical direction sothat the tape is twisted by 90 degrees between a sticking portion andthe reel. Some other tape cutters are furnished with additionalfunctions. For example, a tape cutter includes a rotary plate attachedto the bottom thereof to make a yaw motion with the rotational angle of360 degrees. An other tape cutter can serve as a penholder. Yet anothertape cutter includes a mechanism configured to lift the leading end of atape, after the tape is cut, to thereby enable a user to pick up theraised leading end with the fingers. Moreover, to prioritize safety of afinger, some other tape cutters are equipped with a mechanism forrotating a blade portion to house the cutting edge of the blade, or areequipped with a cover to conceal the same.

For example, a conventional tape cutter includes a linear blade, ratherthan a general saw blade, with a mechanism capable of ensuring safety ofa finger at the cutting edge of a blade. As is understood from T30 byElm Corp., a pair of rotatable ball-like edge guards can be provided onupper opposite sides of a blade to allow a tape to pass between theguard balls while being folded in a V shape and prevent a finger frompassing. Furthermore, as understood from ST51 by Lion Office ProductsCorp., a sliding plate can be provided in front of and adjacently to ablade so that the plate can conceal the cutting edge when the blade isnot used. When a user applies pressing force to cut a tape, the tape ismoved downward and pulled forward by the applied force while atape-sticking portion swings in the back-and-forth direction to move theplate downward. However, the above-described products have some problemsin usability. Strictly speaking, neither one of the products can preventa finger from touching the cutting edge of a blade. Related applicationsare Japanese Laid-Open Patent Application No. hei 1-231763 and JapaneseLaid-Open Patent Application No. hei 1-308359.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

To cut a tape well, use of a sharp blade is desired. However, to attacha sharp blade, a tape cutter is required to ensure safety of a finger atthe cutting edge of the blade. In other words, any sharp blade can beattached to a tape cutter if the tape cutter is capable of preventing afinger from contacting with the cutting edge of the blade.

An object of the present invention is to provide a tape cutter capableof preventing a finger from contacting the cutting edge of a blade, by asticking portion and a guard plate that can slide in the up-and-downdirection and a pair of guard arms configured to be opened/closed whileinterlocking with up/down motion of the sticking portion. Thus, a usercan attach a sharp blade to the tape cutter and can use the tape cuttersafely and comfortably.

Means for Solving the Problems

To attain the above-described object, a tape cutter according to thepresent invention employs the following method.

A tape-sticking portion, separated from a blade, can slide in theup-and-down direction. A pair of arm-like edge guards; i.e., guard arms,provided on opposite sides of the sticking portion, can conceal thecutting edge of a blade while interlocking with up/down motion of thesticking portion, so that the guards are opened when the stickingportion is raised and closed when the sticking portion is lowered.

To enhance safety, a planar edge guard; i.e., guard plate, movable inthe up-and-down direction together with the sticking portion is providedin front of the blade.

To prevent the raised sticking portion from falling due to its ownweight and closing the guard arms after a tape is peeled off thesticking portion, a magnet can be attached to the sticking portion. Whenthe magnet moves upward together with the sticking portion, the magnet,generating magnetic force, can attract the lower edge of the iron blade.Thus, the magnet enables the guard arms to temporarily sustain theopened state.

The sticking portion and its holder can incline when they are pulledtoward the reel side under the tensile force applied to a tape to peelthe tape off the sticking portion. After the tape is peeled off thesticking portion, the sticking portion and its holder return to theiroriginal positions.

The above-described means for solving the problems have the followingfunctions.

When a user pulls a tape to peel it off the sticking portion, the forceinduced by a peel resistance acting on a tape adhesion surface causesthe sticking portion to move upward. On the other hand, when a user cutsthe tape, the tape presses the sticking portion downward. These forcescan be used to automatically open and close the guard arms.

If a magnet is used to temporarily sustain the opened state of the guardarms in a condition where the sticking portion is raised, the resistanceduring a raising operation of the sticking portion is small as comparedwith that found in another method using elasticity and friction of aspring or a resin, or a method using gravity. Furthermore, when themagnet approaches the lower end of the blade, the magnetic force canassist the sticking portion in rising.

To let the sticking portion rise smoothly, a bearing position of thereel is desirably slightly higher than a leading end of the tape if thesticking portion slides in the vertical direction. When such anarrangement is realized, the locus of a top surface of the stickingportion moving in the up-and-down direction can be positioned inside acircular locus along which the leading end of the tape travels in astate where a wound tape is not yet peeled off. However, thisarrangement may add restrictions in designing an appearance. However, ifthe sticking portion inclines toward the reel when a user starts toraise a tape, the distance between the sticking portion and the reeldecreases and the tape is bent loosely between the sticking portion andthe reel. The difference between the sliding direction of the stickingportion and the tape-pulling direction becomes smaller. Therefore, evenif the bearing position of the reel is designed to have a smallerheight, the sticking portion can be raised smoothly.

After the tape is peeled off the sticking portion, the guard arms aresustained in the opened state. In this condition, the guard plate andthe sticking portion positioned in front of or in back of the blade canconceal the cutting edge of the blade. During a tape-cutting operationor when the cutting operation is finished, the guard arms are closed toconceal the cutting edge of the blade.

A user may press the sticking portion down with a finger tointentionally touch the cutting edge of the blade in the state where theguard arms are opened. However, if the sticking portion moves downward,the guard arms are closed. The downward motion of the sticking portionis stopped if the finger is clamped by the guard arms. As the stickingportion is interlocked with the guard arms and cannot move furtherdownward, the finger cannot reach the cutting edge of the blade. If auser performs a tape-cutting operation, the guard plate moves to thelowermost end and its upper end is positioned slightly lower than acutting edge line. If the user intentionally tries to touch the cuttingedge of the blade after completing the tape-cutting operation, the useris required to open the guard arms with the fingers. If the guard armsare opened, the guard plate rises correspondingly. In any event, theuser's finger cannot touch the cutting edge of the blade.

EFFECT OF THE INVENTION

The guard arms, the guard plate, and the sticking portion, which arepositioned above or in front or back of a blade, can conceal the cuttingedge of the blade. A user cannot touch the cutting edge of the bladeeven intentionally. Thus, safety of a finger at the cutting edge of theblade can be reliably ensured. Thus, a sharp blade having a straightcutting edge line can be attached. When a linear blade is used, noindentation is formed along the cutting line of a tape. Therefore, thetape is not torn obliquely when a user applies a pulling force to thecut edge of the tape. Therefore, a user can easily peel off a piece oftape. The cutting line of a piece of tape is good in appearance.

The opening/closing operation of the guard arms can be automatically,without requiring the user's attention, performed using the forceapplied when a piece of tape is peeled off the sticking portion and theforce applied when the piece of tape is to pressed against the stickingportion. In other words, the guard arms can be opened or closed by anoperation substantially similar to that of a conventional common tapecutter.

The sticking portion can incline toward the reel side. Therefore, evenif the reel-bearing position is designed to have a smaller height, thesticking portion can rise smoothly. Therefore, the degree of freedom indesigning the appearance can be increased. Furthermore, using a magnetcapable of sustaining the opened state of the guard arms enables themechanism to operate smoothly and accurately. A tape cutter according tothe present invention can be used widely, although a tape-raising methodis variable, depending on the state in operation or depending on theuser's preference. The problem such that apiece of tape is peeled offthe sticking portion before the sticking portion is completely raisedcan be solved. Therefore, the tape cutter according to the presentinvention can be used for a masking tape or any other tape having alower level of adhesion.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will now be described withreference to the drawings. FIG. 1 is a front view illustrating guardarms in a closed state. FIG. 2 is a front view illustrating a stickingportion in a raised state and the guard arms in an opened state. FIG. 3is a side view illustrating the guard arms in a closed state.

As an arrangement of parts, this mechanism includes essential partsincorporated in a space between a front holder 9 and a rear holder 8. Ablade 6 is fixed to the front holder with screws. Right and left guardarms 3 can rotate about two holder pins 14 protruding from the rearholder. The right and left guard arms are mutually symmetrical about aplane and constitute a mirror-image arrangement.

A sticking portion 4 has a shape symmetrical with respect to the rightand left direction. The sticking portion can slide in the up-and-downdirection between the blade 6 and the rear holder 8. The stickingportion has two elongated holes, which prevent the sticking portion frominterfering with the holder pins 14 protruding from the rear holder. Twointerlocking pins 15, which are offset inward from the holder pins 14,can interlock the sticking portion with the right and left guard arms 3.

The guard arms 3 have proximal ends where holes are provided to receivethe holder pins 14 protruding from the rear holder and elongated holesare opened to receive the interlocking pins 15 protruding the stickingportion. The guard arms 3 rotate about the holder pins 14, which arestationary, while interlocking with the motion of the interlocking pins15 on the sticking portion, which can move. More specifically, the guardarms simultaneously open and close in association with up/down motion ofthe sticking portion. FIG. 4 illustrates a positional relationshipbetween the holder pins 14 and the interlocking pins 15 in a state wherethe guard arms are closed. FIG. 5 illustrates a positional relationshipbetween the holder pins 14 and the interlocking pins 15 in a state wherethe guard arms are opened. The arm portions exposed to the outside havelower and rear cutout portions, which can prevent an operation of thearm portions from interfering with the sticking portion.

A guard plate 5, having a U-shaped configuration and positioned betweenthe front holder 9 and the blade 6 fixed to the front holder, isindependent of the sticking portion. The guard plate 5 has protrusionsprovided on right and left sides thereof, which are engageable withnotches 17 provided on the sticking portion. When integrated, the guardplate 5 and the sticking portion can move together in the up-and-downdirection. FIG. 6 illustrates the position of the blade in a state wherethe guard arms are opened. FIG. 7 illustrates the guard plate assembledwith the sticking portion. The blade 6 is a linear blade.

A magnet 7 is fixed to the lower portion of the sticking portion. Whenthe sticking portion is raised, the magnet 7 can reach the lower end ofthe blade 6 under the magnetic force generated by the magnet 7. FIG. 8illustrates the sticking portion in a lowered state. FIG. 9 illustratesthe sticking portion in a raised state where the magnet is bought intocontact with the blade.

The rear holder 8 is attached to the tape cutter main body via a shaft10, which extends through a lower hole. The rear holder 8 can swing inthe back-and-force direction about the shaft. The rear holder has a rearend portion, which is pressed upward by a coil spring 11 placed on amain body bottom board 13, as illustrated in FIG. 10.

An operation of the above-described mechanism, when used by a user, isdescribed below.

First, if a user pulls a piece of tape to peel it off the stickingportion, the sticking portion is pulled toward the reel side undertensile force of the tape. Both the front and rear holders inclinerearward. Next, the force induced by a peel resistance acting on a tapeadhesion surface causes the sticking portion to move upward. Inassociation with this movement, the guard arms are opened gradually. Themotion is stopped when the magnet fixed to the lower end of the stickingportion is brought into contact with the lower end of the blade. Then,the piece of tape is removed off the sticking portion.

If the tape is pulled out by a required length, the guard arms arerequired to be opened until the tape is pressed against the stickingportion. The magnet can generate a magnetic force sufficient to sustainthis condition. If the tape is peeled off the sticking portion, thefront and rear holders are immediately released from the rearwardlyinclined condition and returned to the original positions by the coilspring.

If a user presses a tape against the sticking portion to cut the tape,the sticking portion is moved downward by the applied force. The guardarms, interlocking with the motion of the sticking portion, aregradually closed while they follow the lowering tape.

For example, in a state where a tape is removed off the sticking portionfor replacement of the tape, the guard arms are closed and can be easilyopened by the fingers of a user. If the guard arms are opened, thesticking portion rises and the magnet sustains the opened state.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view illustrating guard arms in a closed state.

FIG. 2 is a front view illustrating guard arms in an opened state.

FIG. 3 is a side view.

FIG. 4 illustrates a rear holder, a sticking portion, and the guard arms(in a closed state), which are assembled together.

FIG. 5 illustrates the rear holder, the sticking portion, and the guardarms (in an opened state), which are assembled together.

FIG. 6 illustrates the position of a blade.

FIG. 7 illustrates a guard plate attached to the sticking portion.

FIG. 8 is across-sectional view taken along a line A-A passing throughholder pins 14.

FIG. 9 is across-sectional view taken along a line B-B passing throughinterlocking pins 15.

FIG. 10 is a partly sectional view illustrating a central portion.

EXPLANATIONS OF REFERENCE NUMERALS

-   1 tape-   2 reel-   3 guard arm-   4 sticking portion-   5 guard plate-   6 blade-   7 magnet-   8 rear holder-   9 front holder-   10 shaft-   11 coil spring-   12 main body-   13 main body bottom board-   holder pin-   15 interlocking pin-   16 screw-   17 notch

1. A tape cutter comprising a tape-sticking portion separated from ablade and configured to slide in the up-and-down direction and a pair ofarm-like edge guards provided on opposite sides of the sticking portionand configured to be opened/closed while interlocking with up/downmotion of the sticking portion.
 2. The tape cutter according to claim 1,wherein a planar edge guard movable in the up-and-down directiontogether with the sticking portion is provided in front of the blade.3-4. (canceled)